Navigating an R&S MXO3 as a High School Student

I am a high school student with no prior experience using oscilloscopes. So when I was asked to write a blog about the Rohde & Schwarz (R&S) MXO3 oscilloscope, I started sweating right through my polo! I had no idea how to turn one on, let alone write about it. I quickly realized how much there was to learn, but was very excited.

As a first-time user, I was able to test how accessible the R&S MXO3 features are to someone new to electrical engineering. I found it passed with flying colors, and this blog will be a summary of my journey using this oscilloscope as a beginner.

There is an I in Oscilloscope, but there Should be no P in Pool

I started my summer teaching swim lessons at my local pool, but the word “oscilloscope” piqued my interest. So I quit, because 1st graders can’t stop peeing in pools, and I wanted to spend my time learning from the Signal Edge Solutions team instead. They are the smartest people I know based on their ability to make it to restrooms without accidents. The first thing Ben told me about the R&S MXO3 was that it’s a lunchbox. Even after Marshall showed me the basic applications of the oscilloscope, I was still questioning how it could possibly hold a hot dog. 

The Cost

One of the first things I did was look up the cost. I thought the price was reasonable, because it’s about the same as a Louis Vuitton purse of similar size. Then again, one can actually store hot dogs, and the other lights up. The MXO5 costs more than four Louis Vuitton purses, so although I was sadly handed the smaller box, I knew my mom would be relieved; if I broke the MXO3, we would only sell one of her purses instead of four. 

I wanted to compare the MXO3 and MXO5 because Ben said the MXO5 was his favorite, and I was curious why he left me with his lunchbox that can’t hold his lunch. The table below highlights how the MXO5 is more expensive because it offers more features, while the MXO3 was designed to be a general-purpose device. 

Figure 1: A table showing characteristics of R&S MXO3 and MXO5

Figure 2: MXO3 on the left and MXO5 on the right

Noise Floor

This led me to spend more time reading the product brochure, where I found R&S claims the noise floor of the MXO3 to be less than 50 µV RMS noise with 100 MHz of bandwidth. At the time I had no idea what that meant, even after Googling every word I still wasn’t sure. Luckily, Marshall had a more understandable explanation and showed me how to find it. Now I can tell you the oscilloscope's noise floor is like a calm ocean with small waves. You can easily see a large boat, but small buoys will get lost in the waves. Marshall is very patient, because even though it took many demonstrations and a nightmare about oscilloscopes eating me alive, I can now navigate to the noise floor independently.

Figure 3: The R&S MXO3 noise floor

I found the noise floor to range between 50-150 µV with 1 GHz of bandwidth, but I doubted myself because this was different from the brochure. After three more attempts and a small panic, I trusted the numbers more than my confusion. I realized that greater bandwidth meant a larger noise floor and calmed my nerves. To make another comparison between the MXO3 and MXO5, the MXO5 is capable of about 60 µV with 2 GHz of bandwidth, so you can see it’s more expensive for a reason. 

Weight and Usability

I have zero arm strength, but this oscilloscope is easy to pick up and move around, which is a nice feature for anyone looking to save space on their workbench. As someone used to touchscreens, I appreciate not having to connect a mouse like Ben and my grandparents did. When you search the web for “R&S MXO3 reviews,” not a lot shows up, but I did come across a community forum that I spent hours reading through. There, people claimed their MXO3 was missing encoder steps, causing a delay on the touchscreen. Once again, I had to Google what encoder steps were, but I didn’t worry too much because I did not experience the delay. To save you time, it means the system misses tiny movements, which causes missed signals and therefore choppy motion on screen. 

It took me a while to realize simple features, so if you are new, like I was, I will save you some time. There is a switch on the back that you have to flip before you can turn it on. I discovered this after pretending to pet Ben’s dogs while I was Googling why the power button wasn’t working. There are also feet in the front that can tilt the oscilloscope and save you from backaches. The lighting of the knobs and buttons is intense, and I would highly recommend microwaving your lunch for an extra minute so you can figure out how to turn it down.

Triggering

Marshall demonstrated a trigger on the MXO3 at least three times. I remember trying to do it on my own, and I clicked “zone trigger" instead. That’s how I accidentally discovered my favorite feature. The zones can be any shape with four points placed anywhere. You can choose whether the signal can or cannot enter the zone, as well as overlap zones, in case 4 points are not enough. I enjoyed exploring it because there were so many possibilities. 

Figure 4: Zone triggers shown on the R&S MXO3

Conclusion

A few weeks ago, I couldn’t tell you what an oscilloscope did, and while I am nowhere near calling myself an expert, the R&S MXO3 made the first step a lot less intimidating. I hope this blog helps other users new to the oscilloscope world, or at least makes someone laugh while reading about my trials and tribulations of navigating one.